Question

IN PYTHON 3 LANGUAGE

The windows generator takes an iterable and two ints (call them n and m; with m’s default value 1) as parameters: it produces lists of n values: the first list contains the first n values; every subsequent list drops the first m from the previous list and adds the next m values from the iterable, until there are fewer than n values to put in the returned list.

call iter and next directly, and use a list that always contains n values, so it doesn’t violate the conditions for using iterables

SAMPLE OUTPUT:

For example:

for i in windows('abcdefghijk', 4,2):

print(i,end='')

prints ['a','b','c','d'] ['c','d','e','f'] ['e','f','g','h'] ['g','h','i','j'].

for i in windows('abcdefghijk', 3,2):

print(i,end='')

prints ['a', 'b', 'c'], ['c', 'd', 'e'], ['e', 'f', 'g'], ['g', 'h', 'i'], ['i', 'j', 'k']

Answer 1

def windows(itr, n, m):
    lst = []
    index = 0
    for i in range(index, len(itr)):
        l = []
        for j in range(n):
            if j + index < len(itr):
                l.append(itr[j + index])
        if len(l) == n:
            lst.append(l)
        index += m
    return lst


for i in windows('abcdefghijk', 4, 2):
    print(i, end='')

print()

for i in windows('abcdefghijk', 3, 2):
    print(i, end='')